Ignition apparatus



Oct. 28, 1941. J; R. FREI ETAL 2,250,663

IGNITION APPARATUS Filed April 18, 1940 2 Sheets-Sheet 1 j INVENTORS M F mu; BY W 6? M flmm ATTORNEY Oct. 28, 1941. J. R. FREI ErAl.

' IGNITION APPARATUS Filed April 18; 1940 2 Sheets-Sheet 2 llllzlllllllllllllln a INVENTO W R 5 BY u a c ATTORNEY Patented Oct. 28, 1941 IGNITION APPARATUS Jakob n. Frel, Sidney, and William 0. Pross, Bainbridge, N. Y., assignors to Bendix Aviation Corporation, South Bend, lnd., a corporation of Delaware Application April 18, 1940, Serial No. 330,232

14 Claims.

This invention relates to ignition apparatus, and more particularly to current generating and distributing means.

One of the objects of the present invention is to provide a novel magneto generator adapted for use in the ignition system of an internal combustion engine.

Another object of the invention is to provide a novel magneto which is so constructed as to facilitate timing the various parts thereof with each other after assembly.

Still another object is to provide a novelly constructed magneto wherein the low tension circuit breaker cam and the rotatable distributor element are mounted on a common shaft and are independently adjustable with respect to said shaft.

A further object is to provide novel ignition current generating means which may be nonadjustably attached to an engine as well as to the radio shielding harness associated with the engine.

A still further object is to provide novel means for effecting the necessary electrical connections to the ignition coil of the magneto.

Another object is to provide a magneto wherein the parts are novelly constructed and assembled so that inspection and adjustment thereof are greatly facilitated and so that the length as well as the number of electrical leads within the magneto casing are materially reduced.

Anoth'er object is to provide a magneto equipped with novel timing features whereby the speed of production may be increased and the cost of production may be decreased.

The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying drawings. however, that the drawings are for the purpose of illustration only and are not intended to define the limits of the invention, reference for this latter purpose being had primarily to the appended claims.

In the drawings, wherein like reference characters refer to like parts throughout the several views;

Fig. 1 is a side elevation, mostly in section and It is to be expressly understood,

in section and with parts broken away, the end cover plate thereof being removed.

A single embodiment of the invention is illustrated in the accompanying drawings, by way of example only, in the form of a magneto adapted for use on a 14 cylinder internal combustion engine. .As shown, the same comprises a housing or casing made up of a main section 5, a top cover 6 and an end cover 1. Flanged portion 8 of the main casing section is adapted for housing a rotatable distributor element to be later described, and in one suitable embodiment is directly attachable to a portion 9 of a radio shielding harness manifold Ill, only partially shown, which portion houses a distributor block ll of any suitable, well-known construction. A plate I! which is detachably secured to the base of easing section 5 by bolts l3 constitutes a support for the magneto rotor as well as means for securing the magneto to an engine casing. It will be understood that the distributor block housing 9 need not be attached to or formed integrally with the shielding harness but may, if desired, be a separate unit or an integral part of the magneto casing.

Mounted in the lower central part of main casing section 5 with the axis thereof extending vertically is a multiple pole magnetic rotor l4 comprising a cylindrical, axially magnetized permanent magnet l5 and eight laminated softiron pole shoes l6, four at each -'end of the ma net, adapted to cooperate ins-a manner wellknown in the art with laminated stator pole pieces I! which are only partially shown. The lower 'end of rotor shaft [8 is journalled in plate l2 and the upper end thereof is journalled in an internal portion IQ of casing section5 by means of roller thrust bearings 2!! and 2|, re-

spectively.

In order that the magneto may be rigidly secured to the engine in a predetermined position by means of bolts extending through holes 22 in plate l2, means are provided on the lower end of shaft 18 whereby the latter may be adjustably coupled to a driving member 23 (Fig. 1) of the engine, said means preferably being such that angular adjustments of less than one degree may be efiected to properly coordinate or time the rotation of rotor ll with the engine crankshaft. In the form shown, said coupling means comprises an externally splined sleeve 24, which is loosely mounted on shaft l8 and is adapted to drlvably engage the internally splined engine member 21. The outer or lower edge of sleeve 24 is provided with a plurality of ratchet teeth 25, as best seen in Fig. 2, adapted to mesh with an equal number of ratchet teeth 26 on the adjacent face of a ring 21 that is also loosely mounted on shaft l8. The other or lower face of ring 2'! is provided with a plurality of ratchet teeth 28, numbering one more or less than teeth 26 and adapted'to mesh tooth for tooth with ratchet teeth 29 on the adjacent edge of a second sleeve 30 that is keyed or splined to shaft l8 for rotation therewith. The entire coupling assembly 24, 21, 30 may be releasably held with teeth 25, 26 and teeth 28, 29 in driving engagement by a nut 3i threaded onto shaft l8 so that energy may be transmitted from engine member 23 through sleeve 24, ring 21 and sleeve 30 to shaft l8.

When it is desired to make an angular adjustment of rotor I4 relative to driving member 23 and, hence, relative to the engine crankshaft, nut 3| is loosened sufficiently so that theratchet teeth on one of the sleeves 24 or 30 can pass over the corresponding teeth on ring 21. By now angularly moving the rotor first in one direction an amount equal to the pitch of teeth 26 and then in the opposite direction an amount equal to the pitch of teeth 28, or vice versa. angular adjustments equal to the difference in the pitch of said teeth may be effected. Since this coupling, per se, does not constitute a part of the present invention, it is not believed that a more detailed description of the construction and operation thereof is necessary.

Mounted to the right of rotor l4, as viewed in Fig. 1, in a compartment 32 formed by casing and removable cover 1 is an ignition coil comprising the usual primary and secondary windings P and S, respectively, wound around a laminated metallic core 33 and housed in casing 34 of insulating material, such as molded Bakelite. The ends of core 33 are attached in any suitable manner to the ends of stator members thereby completing the magnetic path through the rotor and serving as a support for the coil and its housing 34. Molded in said housing and extending across one face thereof is a metallic bar 35 which is electrically connected by means also embedded in the housing structure to the adjacent ends of the primary and secondary coil windings which it is desired to ground. The projecting ends of bar 35 are secured by screws 36 (Fig. 2) to the magneto casing to thus effect a ground connection and afford further support for the coil housing. Also molded in casing 34 adjacent the same face or side thereof is a second metallic bar 31 (Fig. 1) to which the insulated terminal of the primary winding of the coil is connected by means of a conductor 38.

In order to eliminate loose or long wire connections between the ignition coil and a condenser 39 (Fig. 1), the latter is mounted directly on casing 34 in a novel manner. As shown, bars 35 and 31 are provided with threaded countersunk openings which are adapted to receive set screws 40 and 4f that extend through ears on the condenser casing. Screw 40 effects a connection between one terminal of condenser 39 and ground, while screw 4| effects a connection between the other terminal of the condenser and the insulated end of the coil primary winding which is connected, by means of a lead 42, to one side of a circuit breaker to be later described. Bar 31 is also connected by a lead 31' to a socket 43 in the side of casing section 5, which socket may, in turn, be connected to ground through a shielded cable 44 and an ignition switch (not shown).

Novel means are also provided for connecting the high tension end of the secondary winding of the ignition coil to the distributor to be hereinafter described. In the form shown, said means comprises a socket 45 molded as an integral part of coil casing 34 and a metallic insert 46 molded in said casing at the base of said socket, said insert being internally connected by a lead 46' with the secondary Winding of the ignition coil. Socket 45 is in axial alignment with an opening in the side of casing 5 and a threaded bushing 41 fitted in said opening. A plug connector 48 which constitutes an extension of .a shielded cable 49 slidably extends through said bushing and into socket 45 for contact with insert 46, said connector being held in position by a nut 50 threaded onto bushing 41 exteriorly of casing 5. In order to render the magneto adaptable for use on either the right or left-hand side of a dual ignition engine, sockets for cables 44 and 49 are provided on both sides of easing 5, the ones which are not in use' being closed by means of suitable caps 5|.

The upper end of rotor shaft 18 extends into a compartment 52 which is closed by cover 6 and is fitted with a bevel gear 53 that meshes with a second bevel gear 54 mounted on a horizontal shaft 55 for rotation therewith, the latter shaft being journalled in roller bearings 56, 56 in the opposite side walls of compartment 52. Gear 53 is preferably drivably associated with shaft l l by means of axial splines or serrations 51 which, due to features of the invention to hereinafter appear, need not have any particular relation to the positioning of pole shoes IS on the rotor, thereby materially reducing the precision with which said splines or serrations need be cut and eliminating any possibility of improper assembly. When the embodiment illustrated is used in connection with a 14 cylinder engine, rotor I4 is driven at seveneighths engine crankshaft speed and the speed ratio between the rotor and shaft 55 is seven to four, thereby driving said shaft at one-half engine crankshaft speed. The upper end of rotor shaft [8 and both ends of shaft 55 are surrounded by suitable packing rings 58, such as Chicago Rawhide packing rings, in order to render compartment 52 grease-tight. The latter is preferably wholly or partially filled with grease during operation of the magneto in order to provide continuous lubrication for gears 53, 54 and bearings- 56. If desired, the positions of bearing 2| and packing ring 58 around shaft [8 may be reversed so that said bearing will also be continuously lubricated from compartment 52.

Mounted on the right end of shaft 55, as viewed in the drawings, and directly above coil casing 34 is a circuit breaker cam 59 which is adapted to periodically open a pair of contacts 50 and SI the former of which is connected to lead 42 and movable by a cam follower 62 while the latter contact is stationary and connected to ground through the magneto casing. Contact points and BI are thus connected in series with the primary winding of the ignition coil 34 and in shunt with condenser 39. Said contact points and cam follower 62, are shown as a single unit adjustably mounted by means of a bracket 63 upon a plate 54 which is, in turn, fixed to casing section 5. Since cam 59 is rotated at one-half engine crankshaft speed, as pointed out above, the same is provided with one lobe for each engine cylinder, the spacing of said lobes being such as to compensate for the irregularity of the piston movements in a radial type engine.

aaeacea in order to obtain proper timing of the opening of contact points 50, 6|, with respect to the rotation of rotor l4, cam 59 is coupled to shaft 55 by means'of an adjustable coupling which is.

similar in construction and operation to the coupling on the lower end of rotor shaft l8 heretofore described. Cam 59, itself, corresponds to sleeve 24 of the previously described coupling, a ring 55 and a sleeve 65 correspond to ring 21 and sleeve 30, respectively, and the unit as a whole is held in operative engagement on shaft 55 by a nut 61. Very fine angular adjustments of cam 59 relative to shaft 55 may thus be readily effected independently of any other parts of the magneto. It will also be noted that when the magneto is installed on an engine, the breaker mechanism and the ignition coil may be readily inspected and adjusted by removing cover, I.

On the other or left-hand end of shaft 55 in portion 8 of easing is a rotatable distributor element or finger 68 comprising a mounting plate or hub 69 to which is secured an insulating block 10. Molded in the latter on the axis of rotation thereof is a central contact H which is connected to one terminal of a condenser 13 mounted in a recess in block Ill. Also supported by an arm molded in block 10 is a peripheral contact 12 which is electrically connected to the opposite terminal of condenser 13. Contact H is adapted to have a brushing engagement with a contact 74 in distributor block II, which contact is, in turn, connected to high tension supply cable 49 through shielding harness 9, l0, and contact 12 is moved successively by rotation of shaft 55 into operative relation with a plurality of annularly disposed contacts 15 in distributor block I I, each of the latter contacts being, in turn, connected to a spark plug of the engine in any suitable manner welt-known in the art.

Hub portion 69 of distributor finger 68 is drivably associated with shaft 55 by means of aplurality of splines 16 equally spaced entirely around the periphery of the shaft. The angular extent of each of the splines 16 and the angular extent of the grooves between said splines are so chosen with relation to the number of pole shoes on rotor l4 and the speed ratio between shafts I8 and that distributor finger 68 may be mounted Y on shaft 55 so as to be properly timed with the rotor and the circuit breaker. In the illustrated embodiment, thirty six splines are employed so that in at least one position finger 58 will be wthin five-sevenths of one degree of being in perfect time with rotor l4, 1. e., so that contact 12 will lack no more than this small angular distance of being in perfect cen'ter-to-center alignment with one of the contacts 15 each time a high tension discharge occurs. Cam 59 may be adjusted on shaft 55 to effect highv tensiondischarges at predetermined rotor positions, and

distributor finger 68 may be adjusted with relation to these predetermined rotor positions. The rotor may then be timed with relation to the engine crankshaft by means of the adjustable coupling at the lower end of rotor shaft l8.

shown, comprises one or more vertically extending passages 82 (only one of which is shown) bored in a boss on the rear or trailing wall of casing section 5, said passages terminating at their upper ends near the bottom of distributor compartment Ill. The lower end of passage 82 connects with a horizontally extending passage 83 that communicates with the atmosphere outside of the magneto housing. Passage 82 is made relatively long in order to prevent water being carried therethrough into thehousing by air currents. If desired, a tube (not shown) may be connected to the outer end of passage 83 and terminated at a point where there is not too much air disturbance.

There is thus provided a novel magneto and distributor combination wherein the various moving parts may be readily timed with relation to one another'and with relation to the engine on which it is mounted, and wherein the parts are arranged and housed in such a manner as to facilitate inspection and to provide for constant lubrication at most of the points requiring lubrication. Novel means are also provided for making the necessary electrical connections between the ignition coil, condenser, circuit breaker, distributor, ground and ignition switch whereby the length and number of wires within the magneto housing are greatly reduced, thereby minimizing the probability of failure in the ignition system due to chafing or breaking of wires. The magneto provided is also adapted for rapid production at comparatively low cost and requires a minimum of space on the engine since no angular adjustments of the magneto casing for timing purposes are necessitated.

Although only a single embodiment of the invention is illustrated and described, it is to be expressly understood that the same is not limited thereto. For example, the invention might be incorporated in a magneto designed for use on engines having a smaller number of cylinders, or in magnetos provided with a different rotor structure. Various other changes may also be made, particularly in the design and arrangement of parts illustrated, without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art. Fora definition of the limits of the invention, reference is had primarily to the appended claims.

What is claimed is:

1. A magneto comprising a casing, a magnetic rotor mounted therein, said casing having a grease-tight compartment in which one end of said rotor terminates, a shaft extending through said compartment at right angles to the axis of rotation of said rotor, means in said compartment for drivably connecting said rotor and shaft, and a distributor element and a circuit breaker cam mounted on said shaft at opposite ends thereof outside of said compartment.

2. A magneto comprising a housing, a magnetic rotor in the latter, stationary flux conducting elements in cooperative relation with said rotor, an ignition coil having a metallic core secured to said elements, an insulating casing around said coil, a pair of metallic members molded in said casing, a condenser, means including said metallic members for mounting said condenser on said casing whereby opposite terminals of said condenser are electrically connected to said members, means connecting opposite ends of the primary winding of said coil to said members, and means connecting one of said members to ground through said housing.

3. In a magneto, an ignition coil, a molded insulating housing for said coil, a pair of metallic inserts molded in said casing, means connecting the adjacent ends of the primary and secondary windings of said coil to one of said inserts, means connecting the other end of said primary winding to the other of said inserts, a condenser, and means for mounting said condenser on said casing including screws threadedly engaging said inserts whereby opposite terminals of said condenser are electrically connected to different ones of said inserts.

4. In apparatus of the class described, an ignition coil comprising primary and secondary windings, a casing of electrical insulating material surrounding said coil, a pair of metallic inserts in said casing electrically connected to opposite ends of said primary winding, an electrical condenser, common means for physically securing and electrically connecting the terminals of said condenser to said metallic inserts.

5. In a magneto, a housing, an ignition coil comprising primary and secondary windings, an insulating casing forsaid coil, a pair of metallic inserts in said casing, means for connecting one of said inserts to ground through said housing, means electrically connecting one end of each of said windings to said grounded insert, means connecting the other end of the primary winding to the other of said inserts, a socket connected to said casing, a metallic insert at the base of said socket, means connecting the other end of said secondary winding to said last-named insert, a plug connector adapted to slidably extend into said socket for electrical connection with said last-named insert, and a condenser physically and electrically connected to said first-named pair of inserts.

6. In apparatus of the class described, an ignition coil comprising primary and secondary windings, an insulating casing for said coil, a pair of metallic inserts molded in said casing, a condenser physically and electrically connected to said pair of inserts, means for connecting one of said inserts to ground, a circuit breaker, and means for connecting the windings of said coil and said circuit breaker to said metallic inserts whereby said circuit breaker is connected in series with said primary winding and in shunt with said condenser.

7. In a magneto, a housing, an ignition coil comprising primary and secondary windings, an insulating casing for said coil, a pair of metallic inserts in said casing, means for connecting one of said inserts to ground through said housing, means electrically connecting one end of each of said windings to said grounded insert, means connecting the other end of the primary winding to the other of said inserts, a socket connected to said casing, a metallic insert at the base of said socket, means connecting the other end of said secondary winding to said last-named insert, and a plug connector adapted to slidably extend into said socket for electrical connection with said last-named insert.

8. In a magneto, a housing having an opening therein, a bushing in said opening, an ignition coil comprising primary and secondary windings mounted in said housing, an insulating casing surrounding said coil, said casing having a socket formed therein in axial alignment with said opening, a metallic insert in said socket, means connecting the output end of said secondary winding to said insert, a terminal plug-in cohnector slidably extending through said bushing into said socket for electrical engagement with said insert, and means for removably securing said connector against removal from said socket.

9. In a magneto, a housing, an ignition coil comprising primary and secondary windings mounted in said housing, plug and socket connecting means for each of said windings, and means exterior of said housing for removably securing the plugs of said connecting means in operative position.

10. A magneto comprising a housing, a magnetic rotor mounted therein, a shaft rotatably mounted in said housing, means for drivably connecting said rotor and shaft, an ignition distributor having an element thereof mounted on said shaft, the hub of said element and said shaft having cooperating splines of relatively small angular extent, a circuit breaker comprising a cam mounted on said shaft, means for adjustably coupling said cam to said shaft whereby angular adjustments of less than one degree between said cam and shaft may be effected, and means for drivably connecting said rotor to the engine crankshaft including an adjustable coupling whereby angular adjustments of less than one degree between said rotor and the driving member therefor may be effected.

11. A magneto comprising a housing, a magnetic rotor mounted therein, a shaft rotatably mounted in said housing, means for drivably connecting said rotor and shaft, a current distributing element and a circuit breaker cam mounted on said shaft at opposite ends thereof so that the same may be independently angularly adjusted relative to said shaft.

12. A magneto comprising a housing, a magnetic rotor mounted therein, a shaft rotatably mounted in said housing, means for drivably connecting said rotor and shaft, an ignition distributor having an element thereof mounted on said shaft, the hub of said element and said shaft having cooperating splines of relatively small angular extent, a circuit breaker comprising a cam mounted on said shaft, and means for adjustably coupling said cam to said shaft whereby said element and said cam may be independently angularly adjusted relative to said shaft.

13. In a magneto, a housing having distributor, rotor and circuit breaker compartments, all of said compartments being interconnected, and means for ventilating said compartments comprising a relatively vertically extending passage in a wall of said housing, said passage terminating at its upper end in one of said compartments and a second passage in the wall of said housing connecting said first-named passage with the atmosphere.

14. In a magneto, a housing having a plurality of interconnecting compartments, and means for ventilating said compartments comprising a relatively vertically extending passage in the trailing or rear wall of said housing terminating at its upper end in one of said compartments and a relatively horizontally extending passage in said wall connecting said first-named passage with the atmosphere outside of said housing, said first-named passage being relatively long to prevent water being carried into the housing therethrough by air currents.

JAKOB R. FREI. WILLIAM C. PROSS. 

